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Title: Productions of I, I{sup *}, and C{sub 2}H{sub 5} in the A-band photodissociation of ethyl iodide in the wavelength range from 245 to 283 nm by using ion-imaging detection

Abstract

Photodissociation dynamics of ethyl iodide in the A band has been investigated at several wavelengths between 245 and 283 nm using resonance-enhanced multiphoton ionization technique combined with velocity map ion-imaging detection. The ion images of I, I{sup *}, and C{sub 2}H{sub 5} fragments are analyzed to yield corresponding speed and angular distributions. Two photodissociation channels are found: I(5p {sup 2}P{sub 3/2})+C{sub 2}H{sub 5} (hotter internal states) and I{sup *}(5p {sup 2}P{sub 1/2})+C{sub 2}H{sub 5} (colder). In addition, a competitive ionization dissociation channel, C{sub 2}H{sub 5}I{sup +}+h{nu}{yields}C{sub 2}H{sub 5}+I{sup +}, appears at the wavelengths <266 nm. The I/I{sup *} branching of the dissociation channels may be obtained directly from the C{sub 2}H{sub 5}{sup +} images, yielding the quantum yield of I{sup *} about 0.63-0.76, comparable to the case of CH{sub 3}I. Anisotropy parameters ({beta}) determined for the I{sup *} channel remain at 1.9{+-}0.1 over the wavelength range studied, indicating that the I{sup *} production should originate from the {sup 3}Q{sub 0} state. In contrast, the {beta}(I) values become smaller above 266 nm, comprising two components, direct excitation of {sup 3}Q{sub 1} and nonadiabatic transition between the {sup 3}Q{sub 0} and {sup 1}Q{sub 1} states. The curve crossing probabilities are determined tomore » be 0.24-0.36, increasing with the wavelength. A heavier branched ethyl group does not significantly enhance the I(5p {sup 2}P{sub 3/2}) production from the nonadiabatic contribution, as compared to the case of CH{sub 3}I.« less

Authors:
; ; ; ;  [1];  [2];  [2];  [2];  [2];  [2];  [2];  [2]
  1. State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, Beijing 430071 (China)
  2. (China)
Publication Date:
OSTI Identifier:
20991219
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 126; Journal Issue: 6; Other Information: DOI: 10.1063/1.2435341; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; BRANCHING RATIO; DISSOCIATION; IODIDES; IODINE IONS; METHYL IODIDE; MULTI-PHOTON PROCESSES; PHOTOIONIZATION; PHOTOLYSIS; REACTION KINETICS

Citation Formats

Tang, Ying, Lee, Wei-Bin, Hu, Zhengfa, Zhang, Bing, Lin, King-Chuen, Graduate School of Chinese Academy of Sciences, Wuhan, Beijing 437001, Department of Chemistry, National Taiwan University, Taipei 106, Taiwan, Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, Beijing 430071, Graduate School of Chinese Academy of Sciences, Wuhan, Beijing 437001, Department of Chemistry, National Taiwan University, Taipei 106, Taiwan, and Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan. Productions of I, I{sup *}, and C{sub 2}H{sub 5} in the A-band photodissociation of ethyl iodide in the wavelength range from 245 to 283 nm by using ion-imaging detection. United States: N. p., 2007. Web. doi:10.1063/1.2435341.
Tang, Ying, Lee, Wei-Bin, Hu, Zhengfa, Zhang, Bing, Lin, King-Chuen, Graduate School of Chinese Academy of Sciences, Wuhan, Beijing 437001, Department of Chemistry, National Taiwan University, Taipei 106, Taiwan, Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, Beijing 430071, Graduate School of Chinese Academy of Sciences, Wuhan, Beijing 437001, Department of Chemistry, National Taiwan University, Taipei 106, Taiwan, & Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan. Productions of I, I{sup *}, and C{sub 2}H{sub 5} in the A-band photodissociation of ethyl iodide in the wavelength range from 245 to 283 nm by using ion-imaging detection. United States. doi:10.1063/1.2435341.
Tang, Ying, Lee, Wei-Bin, Hu, Zhengfa, Zhang, Bing, Lin, King-Chuen, Graduate School of Chinese Academy of Sciences, Wuhan, Beijing 437001, Department of Chemistry, National Taiwan University, Taipei 106, Taiwan, Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, Beijing 430071, Graduate School of Chinese Academy of Sciences, Wuhan, Beijing 437001, Department of Chemistry, National Taiwan University, Taipei 106, Taiwan, and Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan. Wed . "Productions of I, I{sup *}, and C{sub 2}H{sub 5} in the A-band photodissociation of ethyl iodide in the wavelength range from 245 to 283 nm by using ion-imaging detection". United States. doi:10.1063/1.2435341.
@article{osti_20991219,
title = {Productions of I, I{sup *}, and C{sub 2}H{sub 5} in the A-band photodissociation of ethyl iodide in the wavelength range from 245 to 283 nm by using ion-imaging detection},
author = {Tang, Ying and Lee, Wei-Bin and Hu, Zhengfa and Zhang, Bing and Lin, King-Chuen and Graduate School of Chinese Academy of Sciences, Wuhan, Beijing 437001 and Department of Chemistry, National Taiwan University, Taipei 106, Taiwan and Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan and State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, Beijing 430071 and Graduate School of Chinese Academy of Sciences, Wuhan, Beijing 437001 and Department of Chemistry, National Taiwan University, Taipei 106, Taiwan and Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan},
abstractNote = {Photodissociation dynamics of ethyl iodide in the A band has been investigated at several wavelengths between 245 and 283 nm using resonance-enhanced multiphoton ionization technique combined with velocity map ion-imaging detection. The ion images of I, I{sup *}, and C{sub 2}H{sub 5} fragments are analyzed to yield corresponding speed and angular distributions. Two photodissociation channels are found: I(5p {sup 2}P{sub 3/2})+C{sub 2}H{sub 5} (hotter internal states) and I{sup *}(5p {sup 2}P{sub 1/2})+C{sub 2}H{sub 5} (colder). In addition, a competitive ionization dissociation channel, C{sub 2}H{sub 5}I{sup +}+h{nu}{yields}C{sub 2}H{sub 5}+I{sup +}, appears at the wavelengths <266 nm. The I/I{sup *} branching of the dissociation channels may be obtained directly from the C{sub 2}H{sub 5}{sup +} images, yielding the quantum yield of I{sup *} about 0.63-0.76, comparable to the case of CH{sub 3}I. Anisotropy parameters ({beta}) determined for the I{sup *} channel remain at 1.9{+-}0.1 over the wavelength range studied, indicating that the I{sup *} production should originate from the {sup 3}Q{sub 0} state. In contrast, the {beta}(I) values become smaller above 266 nm, comprising two components, direct excitation of {sup 3}Q{sub 1} and nonadiabatic transition between the {sup 3}Q{sub 0} and {sup 1}Q{sub 1} states. The curve crossing probabilities are determined to be 0.24-0.36, increasing with the wavelength. A heavier branched ethyl group does not significantly enhance the I(5p {sup 2}P{sub 3/2}) production from the nonadiabatic contribution, as compared to the case of CH{sub 3}I.},
doi = {10.1063/1.2435341},
journal = {Journal of Chemical Physics},
number = 6,
volume = 126,
place = {United States},
year = {Wed Feb 14 00:00:00 EST 2007},
month = {Wed Feb 14 00:00:00 EST 2007}
}